This invention relates to devices for mounting surface mounted locks to a door. Because of the wide range of door thicknesses in commercially available doors, difficulties are encountered when fitting and mounting surface mounted locks, such as deadbolt locks. It is common for such locks to be provided with a set of fittings intended to be used with varying door thicknesses so that the correct set of fittings may be selected at the installation site. Even with a set of such fittings, often the fit is imprecise and difficulties in alignment and centering of the lock with respect to the door and the lock mount are common. As a result, installation of surface mounted locks sometimes can be quite difficult, frustrating and time consuming. It is among the primary objects of the invention to provide an improved lock mounting system for surface mounted locks which avoids these and other difficulties.